Heart development Practice Questions

Question 1

A 2-day-old boy is examined on day of discharge from the newborn nursery. He was born at 39 weeks by vaginal delivery to a primigravid mother. The pregnancy and delivery were uncomplicated, and the baby has been stooling, urinating, and feeding normally. Both the patient’s mother and father have no known past medical history and are found to have normal hemoglobin electrophoresis results. Compared to adult hemoglobin, the infant’s predominant hemoglobin is most likely to exhibit which of the following properties?

Accepted Answer

Decreased affinity for 2,3-bisphosphoglycerate

Answer

More likely to form hexagonal crystals

Answer

More likely to cause red blood cell sickling

Answer

Lower affinity for binding oxygen

Answer

Increased affinity for 2,3-bisphosphoglycerate

Question 2

A male neonate is being examined by a pediatrician. His mother informs the doctor that she had a mild fever with rash, muscle pain, and swollen and tender lymph nodes during the second month of gestation. The boy was born at 39 weeks gestation via spontaneous vaginal delivery with no prenatal care. On physical examination, the neonate has normal vital signs. Retinal examination reveals the findings shown in the image. Which of the following congenital heart defects is most likely to be present in this neonate?

Accepted Answer

Patent ductus arteriosus

Answer

Double outlet right ventricle

Answer

Atrial septal defect

Answer

Ventricular septal defect

Answer

Tetralogy of Fallot

Question 3

An 8-year-old girl is brought to the physician by her parents for the evaluation of an episode of unconsciousness while at the playground that morning. She was unconscious for about 15 seconds and did not shake, bite her tongue, or lose bowel or bladder control. Her grandfather died suddenly at the age of 29 of an unknown heart condition; her parents are both healthy. An ECG shows sinus rhythm and a QT interval corrected for heart rate (QTc) of 470 milliseconds. Laboratory studies are within normal limits. Which of the following is the most likely additional finding in this patient?

Accepted Answer

Sensorineural hearing loss

Answer

Oblique palpebral fissures

Answer

Subvalvular ventricular outflow obstruction murmur

Answer

Brachial-femoral pulse delay

Answer

Skin folds between the mastoid process and acromion

Question 4

A 38-year-old woman, gravida 2, para 1, at 24 weeks' gestation comes to the physician for a routine prenatal evaluation. She has no history of major medical illness and takes no medications. Fetal ultrasonography shows a cardiac defect resulting from abnormal development of the endocardial cushions. This defect is most likely to result in which of the following?

Accepted Answer

Atrioventricular septal defect

Answer

Transposition of the great vessels

Answer

Dextrocardia

Answer

Patent foramen ovale

Answer

Sinus venosus defect

Question 5

A 56-year-old man is brought to the emergency department 25 minutes after the sudden onset of severe pain in the middle of his chest. He describes the pain as tearing in quality; it radiates to his jaw. He has hypertension. He has smoked one pack of cigarettes daily for the 25 years. Current medications include enalapril. His blood pressure is 154/95 mm Hg in his right arm and 181/105 mm Hg in his left arm. A CT scan of the chest is shown. The structure indicated by the arrow is a derivative of which of the following?

Accepted Answer

Truncus arteriosus

Answer

Right horn of sinus venosus

Answer

Primitive atrium

Answer

Right common cardinal vein

Answer

Bulbus cordis

Question 6

An investigator is studying the relationship between fetal blood oxygen saturation and intrauterine growth restriction using MRI studies. The magnetic resonance transverse relaxation time (T2) is inversely related to the concentration of deoxyhemoglobin so that high concentrations of deoxyhemoglobin produce a low signal intensity on T2-weighted MRI. In a normal fetus, the T2 signal is most likely to be the highest in which of the following vessels?

Accepted Answer

Ductus venosus

Answer

Descending aorta

Answer

Superior vena cava

Answer

Pulmonary veins

Answer

Right atrium

Question 7

Shortly after delivery, a female newborn develops bluish discoloration of the lips, fingers, and toes. She was born at term to a 38-year-old primigravid woman. Pregnancy was complicated by maternal diabetes mellitus. Pulse oximetry on room air shows an oxygen saturation of 81%. Echocardiography shows immediate bifurcation of the vessel arising from the left ventricle; the vessel emerging from the right ventricle gives out coronary, head, and neck vessels. An abnormality in which of the following developmental processes most likely accounts for this patient's condition?

Accepted Answer

Spiraling of aorticopulmonary septum

Answer

Alignment of infundibular septum

Answer

Fusion of endocardial cushion

Answer

Separation of tricuspid valve tissue from myocardium

Answer

Division of aorta and pulmonary artery

Question 8

A 3-year-old boy is brought to his pediatrician by his parents for a follow-up visit. Several concerning traits were observed at his last physical, 6 months ago. He had developmental delay, a delay in meeting gross and fine motor control benchmarks, and repetitive behaviors. At birth, he was noted to have flat feet, poor muscle tone, an elongated face with large, prominent ears, and enlarged testicles. He takes a chewable multivitamin every morning. There is one other member of the family, on the mother’s side, with a similar condition. Today, his blood pressure is 110/65 mm Hg, heart rate is 90/min, respiratory rate is 22/min, and temperature of 37.0°C (98.6°F). On physical exam, the boy repetitively rocks back and forth and has difficulty following commands. His heart has a mid-systolic click, followed by a late systolic murmur and his lungs are clear to auscultation bilaterally. Several vials of whole blood are collected for analysis. Which of the following studies should be conducted as part of the diagnostic screening protocol?

Accepted Answer

Southern blot with DNA probes

Answer

Northern blot with RNA probes

Answer

Two-dimensional gel electrophoresis

Answer

Western blot

Answer

PCR followed by northern blot with RNA probes

Question 9

A 70-year-old woman presents with substernal chest pain. She says that the symptoms began 2 hours ago and have not improved. She describes the pain as severe, episodic, and worse with exertion. She reports that she has had multiple similar episodes that have worsened and increased in frequency over the previous 4 months. Past medical history is significant for diabetes and hypertension, both managed medically. The vital signs include temperature 37.0°C (98.6°F), blood pressure 150/100 mm Hg, pulse 80/min, and respiratory rate 15/min. Her serum total cholesterol is 280 mg/dL and high-density lipoprotein (HDL) is 30 mg/dL. The electrocardiogram (ECG) shows ST-segment depression on multiple chest leads. Coronary angiography reveals 75% narrowing of her left main coronary artery. In which of the following anatomical locations is a mural thrombus most likely to form in this patient?

Accepted Answer

Left ventricle

Answer

Left atrium

Answer

Aorta

Answer

Right atrium

Answer

Right ventricle

Question 10

A 3175-g (7-lb) male newborn is delivered at 39 weeks' gestation to a 29-year-old primigravid woman following a spontaneous vaginal delivery. Apgar scores are 8 and 9 at 1 and 5 minutes, respectively. Cardiac examination in the delivery room shows a continuous machine-like murmur. An echocardiogram shows a structure with blood flow between the pulmonary artery and the aorta. This structure is most likely a derivate of which of the following?

Accepted Answer

6th aortic arch

Answer

4th aortic arch

Answer

1st aortic arch

Answer

2nd aortic arch

Answer

3rd aortic arch

Heart development

Study Resources

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Primitive heart tube formation

Cardiac looping

Atrial septation

Ventricular septation

Outflow tract septation

Valve development

Cardiac conduction system development

Coronary vasculature development

Fetal circulation

Congenital heart defects

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About Heart development for USMLE

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